Quick Answer. A low hemoglobin count, also known as anemia, is caused by pregnancy, a menstrual period, a diet low in iron, blood loss, or a disease that causes the body to produce fewer red blood cells or to destroy red blood cells. According to the Mayo Clinic, medications also sometimes cause anemia.
A cytotoxic T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or killer T cell) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.
Key Points. 1  Helper T cells secrete small proteins called cytokines that regulate or assist in the active immune response by activating other immune cells. 2  Cytotoxic T cells (TC cells, or CTLs) destroy virus-infected cells and tumor cells, and are implicated in transplant rejection and autoimmune disease.